Study of incidence of supracondylar process of humerus in the population of
Assam
Abstract
Background: Supracondylar process, in human, is a rare, anomalous, beak-like
bony process on the anteromedial surface of the humerus. It represents the
embryologic vestigial remnant of climbing animals and seen in many reptiles, most
marsupials, cats, lemurs and American monkeys. The present study aims at the
determination of incidence of the supracondylar process of humerus in the
population of Assam. Materials and methods: 80 adult dry humeri were collected
from Anatomy Department, Gauhati Medical College and were examined. Results:
Out of 80 humeri, we found one humerus of left side with a bony projection from
antero-medial surface of its distal shaft. The bone was then examined, studied,
photographed and its dimensions were recorded. Conclusion: Knowledge of this
variation may be of great importance to anatomists and anthropologists, because of
possible link to the origins and relations of the human races.
Introduction
Race estimation from skeletal data has always been a central focus in
anthropology1. Also, knowledge of variations in anatomy which is important to
anatomists, radiologists, anesthesiologists and surgeons, has gained more
importance due to wide use and reliance on computer imaging in diagnostic
medicine2. Morphological differences are the tools being used to find the missing
links between the different stages of evolution. One of such variations is the
“supracondylar” processes.
The spur of the humerus or supracondylar process was first reported by Struthers in
1849. It has been referred to as the “supraepitrochlear”, “supracondyloid”
“epicondyloid” or “a supratrochlear spur” by various authors3. It is a normal
anatomical structure in climbing animals4. In human, it is a rare, anomalous, beaklike bony process on the anteromedial surface of the humerus. It represents the
embryologic vestigial remnant of climbing animals and seen in many reptiles, most
marsupials, cats, lemurs and American monkeys5. It is usually found 5 - 7 cm
above the medial epicondyle. The process projects anteroinferomedially from the
distal third of the humerus and presents in 0.7 to 2.7% of the population 4. A
ligament called Struthers’ ligament extends from the apex of the process to the
medial epicondyle3.
Materials and methods
The study was conducted on 80 humeri which were collected from the 1 st M.B.B.S
students and from the osteology laboratory, Department of Anatomy, Gauhati
Medical College. The bones were examined for any osseous projection from distal
part under day light. Only one humerus of left side was found with an osseous
spine on its distal anteromedial surface. Dimensions of the projection were
recorded by a vernier calliper and the incidence was calculated.
Results
The bony projection was extending obliquely, medially and downward from the
anteromedial surface of the distal humeral shaft approximately 4.4 cm above the
medial epicondyle. This spine was reported & referred to as supracondylar process.
Table1. Showing various measurements of the supracondylar process (bony spine)
Measurement Of Spine (supracondylar Value(in cm)
process)
Length of spine
1.1
Distance of spine from medial epicondyle
4.4
Distance of spine from nutrient foramen
6.5
Breadth at the base of spine
1.5
The incidence calculated in this study is- 1 X 100 = 1.25%
80
Discussion
Incidence varies according to report given by different authors. Percentage of
incidence according to different authors in different population along with incidence
determined from this study in the population of Assam are shown belowTable2: Showing incidence of supracondylar process reported in different studies
SI.No.
Author
Incidence
Population / Race
1
Gruber17 (1865)
2.7%
European race
2
Danforth18 (1924)
0.5%
Mixed (Review)
3
Adachi19 (1928)
0.8%
Mixed (Review)
4
Terry12 (1930)
1.16
5
Terry12 (1930)
0.1%
6
Hrdlicka20 (1923)
7
Dellon21 (1986)
1.15%
European race
8
Parkinson5 (1954)
0.4%
Mixed population
9
Natsis22 (2008)
1.3%
Caucasians
10
Gupta23 (2008)
0.26%
Indians
11
Present study
1.25%
Assam
1%
European race
Negroes
American Indians
There is a high incidence of unilateral supracondylar process of the humerus in
'Cornelia de Lange syndrome', an autosomal recessive trait, occurring in
approximately one in every 10,000 live births6.
It is usually clinically silent, but may become symptomatic by presenting as a mass
or can be associated with symptoms of median nerve compression and claudication
of the brachial artery7. The process ends in a roughened point at which a dense
fibrous band (ligament of Struthers) continues to the medial epicondyle 5. From
embryological point of view, the Struthers ligament lies between the tendon of the
latissimus dorsi and the coracobrachialis and corresponds to the lower part of the
tendon of the vestigial latissimo-condyloideus, a muscle found in climbing
mammals which extends from the tendon of insertion of the latissimus dorsi
muscle to the medial epicondyle8. Rarely, this fibrous band may ossify forming a
supracondylar foramen, a tunnel which transmits the median nerve and the brachial
artery and sometimes a variant ulnar artery9 or the ulnar nerve10. In lower
mammals, the osseo-fibrous tunnel formed by the humerus, supracondylar process
and the Struthers’ ligament serves to protect the nerves and vessels going to the
forearm10. In human, the presence of supracondylar process and the Struthers’
ligament is usually asymptomatic, but also it is an important entrapment site for the
median nerve and brachial artery. Entrapment of brachial artery and median nerve
by this ligament at the level of supracondylar process is known as the
supracondylar process syndrome which can be treated by surgical removal of the
process and ligament11. The compression symptoms include severe paresthesia and
hypersthesia of the hand and fingers, ischemic pain of the forearm, embolization of
the distal arm arteries and disappearance of the radial or ulnar pulse on full
extension and supination of the forearm8,10,16. More rarely, ulnar nerve compression
can also occur if the fibromuscular band from the process, instead of being
attached to the medial epicondyle, extends downward as a band which blends with
the fibrous arch between the two heads of the flexor carpi ulnaris13,14,15. The
anterior surfaces of the humerus are also covered by the brachialis muscle. The
spine is thus likely to be within the sub-stance of the brachialis muscle. This could
probably impair the function of the muscle3. Terry (1925) states that supracondylar
process gives rise to the pronator teres, and occasionally affords insertion to a
persistent lower part of the coracobrachialis12.
A supracondylar process should be differentiated from osteochondroma. The spur
is oriented distally, towards the elbow joint and there is no discontinuity in the
cortex of the humerus. An osteochondroma points away from the joint. X-ray films
of the supracondylar process show an intact underlying humeral cortex, whereas in
an osteochondroma, the cortex of the tumor is continuous with the humeral cortex.
Heterotopic bone such as myositis ossificans may also mimic a supracondylar
process14.
The anteroposterior radiographic view is most important since the lateral view may
fail to show the spur on the anteromedial surface of the humerus14.
Treatment consists of excision of the supracondylar spur and the associated
ligament of Struthers. The spur has been reported to recur, and it is therefore
recommended that the spur be removed together with the overlying periosteum24,25.
CONCLUSION:
We documented the incidence of supracondylar process as 1.25 % in the
population of Assam. The supracondylar process is frequently misjudged as a
pathological condition of the bone rather than as a normal anatomical variation.
Though the supracondylar process is a very rare vestigial structure in humans, yet
it is known to have racial variations. Our finding is closer to 1.3% as reported by
Natsis (2008) studied in caucasian population. Along with the anatomists and
anthropologists, the supracondylar process is equally important for clinicians as it
may be overlooked and there may be misdiagnosis.
Reference
1. William PL, Bannister LH, Berry MM, Collins P, Dyson M, Dussek JE,
Ferguson MWJ, (Ed).Gray’s Anatomy. 38th Ed. Churchill Livingstone. New
York,1999:626.
2. Harry WG, Bennett JD, Guha SC. Scalene muscles and the brachial plexus:
anatomical variations and their clinical significance. Clin. Anat. 1997; 10:
252.
3. Oluyemi Kayode A, Okwuonu Uche C, Adesanya Olamide A, Akinola
Oluwole B, Ofusori David A, Ukwenya Victor O and Odion Blessing I.
Supracondylar and infratubercular processes observed in the humeri of
Nigerians. African Journal of Biotechnology. 2007 Novemver 5; Vol. 6 (21),
pp. 2439-2441.
4. Aydinlioglu A, Cirak B, Akpinar F, Tosun N, Dogan A. Bilateral Median
Nerve Compresion at the Level of Struthers’ Ligament. J. Neurosurg. 2000;
92: 693-696.
5. Parkinson C. The supracondylar process. Radiology. 1954; 62: 556-558.
6. Peters FLM. Radiologic manifestations of the Cornelia de Lange syndrome.
Pediatr Radiol. 1975; 3:41-46.
7. Subasi M, Kesemenli C, Necmioqlu S, Kapukaya A, Demirtas M.
Supracondylar process of the Humerus. Acta Orthop. Belg. 2002; 68 (1):7275.
8. Kessel L, Ring M. The supracondylar spur of the humerus. J Bone Joint
Surg. 1976; 48:765-766.
9. Barnard LB, Mccoy SM. The supracondyloid process of the humerus, J
Bone Joint Surg, 1946; 28(4):845–850.
10.Mittal RL, Gupta BR. Median and ulnar-nerve palsy: an unusual
presentation of the supracondylar process. Report of a case, J Bone Joint
Surg Am, 1978; 60(4):557–558.
11.Pecina M, Boric I, Anticevic D. Intraoperatively Proven Anomalous
Struthers’ Ligament Diagnosed by MRI. Skeletal Radiol. Sep 2002; 31(9):
532-535.
12.Terry RJ. On the Racial Distribution of the Supracondyloid Variation. Am.
J. Phys. Anthropol., 1930; 14: 459-462.
13.Al-Qattan MM, Husband J.B. Median nerve compression by the
supracondylar process:A case report. J. Hand Surg. 1991; 16B: 101-103.
14.Fragiadakis EG, Lamb DW. An unusual case of ulnar nerve compression.
Hand, 1970; 2: 14-16.
15.Thomsen PB. Processus supracondyloidea humeri with concomitant
compression of the median nerve and the ulnar nerve. Acta Orthop. Scand.,
1977; 48: 391-393.
16.Talha H, Enon B, Chevalier JM, L’hoste P, Pillet J. Brachial artery
entrapment: compression by the supracondylar process, Ann Vasc Surg,
1987; 1(4):479–482.
17.Gruber, W.; Ein Nachtrag zur Kenntnis des Processus supracondyloideus
(internus) humeri des Menschen. Arch. Anat. Physiol. Wissen. Med. 1865;
267:367-376.
18.Danforth CH. The Heredity Of Unilateral Variations In Man; Genetics;
1924; 9: 199.
19.Adachi B. Das Arteriensystem der Japaner. Verlag der KaiserlicheJapanische University zu Kyoto, Kenyusha Press, Tokyo.1928.
20.Hrdlicka, A. Incidence of the supracondyloid process in whites and other
races. Am. J. Phys. Anthropol.1923; 6:405-412.
21.Dellon, Lee. Musculotendinous variations about medial humeral epicondyle.
Journal of Hand Surgery (Br), 1986; 11B: 175- 181.
22.Natsis K. Supracondylar process of the humerus: study on 375 Caucasian
subjects in Cologne, Germany. Clin Anat. 2008 Mar; 21(2):138-41.
23.Gupta RK, Mehta CD. A Study of the Incidence of Supracondylar Process of
the Humerus. J. Anat. Soc. India, 2008. 57 (2):111-115.
24.Ivins G K, Fulton MO. Supracondylar process syndrome : A case report. J.
Hand Surg., 1996, 21-A, 279-281.
25.Spinner RJ, Lins RE, Jacobson SR, Nunley J A, Durham NC. Fractures of
the supracondylar process of the humerus. J. Hand Surg. 1994, 19-A, 10381041.
Fig 1: Showing left sided humerus with supracondylar process.
Fig 2: showing only the distal part of the humerus with supracondylar process
Fig 3: Showing the measurement of distance of supracondylar process from nutrient
foramen with vernier calliper